From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A86E828936C; Mon, 5 May 2025 22:15:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746483353; cv=none; b=IArxg89xhEhtLAMEPqXECvE2rA9OwwMDgbZhW+51wBAq0+HQ2yQpz5rq68un4q7zNauVA90ZZbd3IhRWguMbUyqCFy8IFV0nTm+JnOvIj6N7RzJ2k1K3sdzTWXa6SQK7ok2zf6gm7oxfP5Ke/ExaV3+UXnnlfhC9I5tnfgX67dY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746483353; c=relaxed/simple; bh=aMJpZbhrk1lyvoxeycNtnIzcxhgtNw6ZUzzuEiCE7OE=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=WythtABK+Vbsli2dEz31KReEY/WUIkqRjrquj4CxVKqt7dqgnpkJ/DiwwYynueEuRgmSNelEHxfvM1h6qPbLfmGku2MiA31hNCS/KcUQtTLw6/y/EbcL52avk9Pe50QdtPVc+PIC7tCBIIqvJc9AON3OQOPXBJLbcsFVniF6dR0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Fp6TcLrp; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Fp6TcLrp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 096DFC4CEE4; Mon, 5 May 2025 22:15:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746483353; bh=aMJpZbhrk1lyvoxeycNtnIzcxhgtNw6ZUzzuEiCE7OE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Fp6TcLrpAt0Yo/GnDtZlH7IIHuwiLuY3f/Px8lWs5XIrVhy6MJET6QRFbOBxrdhh7 /5QC+3rzGKnNe4UqMnIabeJAr8zuXh3g5IAnq6dmC9jzllqLzKpjdLh+aiJKnnDwxE qL9j1EAUx/PAIbbOOlRD1ZqNxkYHMVhyKrLuHKSTffNBWEoJaXau/G4bN/sgoQBAmI SUQhgItFFz2wvaXPE77FkPwh8vwql4tPi8rQ1IycvAj4VwUePFhvcN7AYxKHjqrr2q N8Cj+9aA9K8/JVz7pv5jL0J9L4IsYnC/Bh1cCs+ti4yMniAYyKzXvfa/FcgjVmDydl rulRBKTPjQfjw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Ryo Takakura , Boqun Feng , Ingo Molnar , Sasha Levin , bigeasy@linutronix.de, clrkwllms@kernel.org, rostedt@goodmis.org, tglx@linutronix.de, peterz@infradead.org, neilb@suse.de, kprateek.nayak@amd.com, csander@purestorage.com, linux-rt-devel@lists.linux.dev Subject: [PATCH AUTOSEL 6.14 049/642] lockdep: Fix wait context check on softirq for PREEMPT_RT Date: Mon, 5 May 2025 18:04:25 -0400 Message-Id: <20250505221419.2672473-49-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250505221419.2672473-1-sashal@kernel.org> References: <20250505221419.2672473-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.14.5 Content-Transfer-Encoding: 8bit From: Ryo Takakura [ Upstream commit 61c39d8c83e2077f33e0a2c8980a76a7f323f0ce ] Since: 0c1d7a2c2d32 ("lockdep: Remove softirq accounting on PREEMPT_RT.") the wait context test for mutex usage within "in softirq context" fails as it references @softirq_context: | wait context tests | -------------------------------------------------------------------------- | rcu | raw | spin |mutex | -------------------------------------------------------------------------- in hardirq context: ok | ok | ok | ok | in hardirq context (not threaded): ok | ok | ok | ok | in softirq context: ok | ok | ok |FAILED| As a fix, add lockdep map for BH disabled section. This fixes the issue by letting us catch cases when local_bh_disable() gets called with preemption disabled where local_lock doesn't get acquired. In the case of "in softirq context" selftest, local_bh_disable() was being called with preemption disable as it's early in the boot. [ boqun: Move the lockdep annotations into __local_bh_*() to avoid false positives because of unpaired local_bh_disable() reported by Borislav Petkov and Peter Zijlstra, and make bh_lock_map only exist for PREEMPT_RT. ] [ mingo: Restored authorship and improved the bh_lock_map definition. ] Signed-off-by: Ryo Takakura Signed-off-by: Boqun Feng Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20250321143322.79651-1-boqun.feng@gmail.com Signed-off-by: Sasha Levin --- kernel/softirq.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/kernel/softirq.c b/kernel/softirq.c index 4dae6ac2e83fb..513b1945987cc 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -126,6 +126,18 @@ static DEFINE_PER_CPU(struct softirq_ctrl, softirq_ctrl) = { .lock = INIT_LOCAL_LOCK(softirq_ctrl.lock), }; +#ifdef CONFIG_DEBUG_LOCK_ALLOC +static struct lock_class_key bh_lock_key; +struct lockdep_map bh_lock_map = { + .name = "local_bh", + .key = &bh_lock_key, + .wait_type_outer = LD_WAIT_FREE, + .wait_type_inner = LD_WAIT_CONFIG, /* PREEMPT_RT makes BH preemptible. */ + .lock_type = LD_LOCK_PERCPU, +}; +EXPORT_SYMBOL_GPL(bh_lock_map); +#endif + /** * local_bh_blocked() - Check for idle whether BH processing is blocked * @@ -148,6 +160,8 @@ void __local_bh_disable_ip(unsigned long ip, unsigned int cnt) WARN_ON_ONCE(in_hardirq()); + lock_map_acquire_read(&bh_lock_map); + /* First entry of a task into a BH disabled section? */ if (!current->softirq_disable_cnt) { if (preemptible()) { @@ -211,6 +225,8 @@ void __local_bh_enable_ip(unsigned long ip, unsigned int cnt) WARN_ON_ONCE(in_hardirq()); lockdep_assert_irqs_enabled(); + lock_map_release(&bh_lock_map); + local_irq_save(flags); curcnt = __this_cpu_read(softirq_ctrl.cnt); @@ -261,6 +277,8 @@ static inline void ksoftirqd_run_begin(void) /* Counterpart to ksoftirqd_run_begin() */ static inline void ksoftirqd_run_end(void) { + /* pairs with the lock_map_acquire_read() in ksoftirqd_run_begin() */ + lock_map_release(&bh_lock_map); __local_bh_enable(SOFTIRQ_OFFSET, true); WARN_ON_ONCE(in_interrupt()); local_irq_enable(); -- 2.39.5